@article{PismaZhETF.20.332,
    title = {Compression and focusing of a neutron gas by moving the moderator},
    author = {Askar'yan, G. A. and Namiot, V. A.},
    journal = {Письма в ЖЭТФ},
    volume = {20},
    issue = {5},
    pages = {332},
    year = {1974},
    doi = {},
    url = {http://jetpletters.ru/ps/0/article_27266.shtml},
}